"We got a vehicle registration fee of 20 per cent on this vehicle as per rules," said an official on condition of anonymity. Sources said that the reason behind the high cost is not just the make of the vehicle, but also the alterations made, both in the exteriors and interiors.

The BMW is totally bullet-proof with armour protection on the chassis and windows because of security concerns for Mr Ambani.

Sources told NDTV, "The car is a regular BMW 760i which costs 1.9 crore on road. But as per Mr Ambani's Z category security requirement, it was armoured by BMW Germany. Since the import duty on armoured cars is 300%, the cost of the car ballooned to Rs 8.5 crore, hence the high registration cost."

The armoured car has reportedly been specially manufactured in Germany.

Since 2013, Mr Ambani has been provided with Z-category security because of threats received by mail. He reimburses the government for the cost of the armed commando squad that guards him.